Slotting method, slotting device, and method of manufacturing metal sheet brake shoe by slotting

ABSTRACT

The present invention provides a slotting method in which, during production of a metal sheet V-pulley or the like, slitting can be correctly easily performed at an arbitrary position in the thickness direction of an outer peripheral face of a blank. A blank housing recess ( 5 ) a depth of which is smaller than the thickness of a disk-like metal blank ( 1 ) is formed in an upper face of a lower rotary die ( 4 ) on which the blank ( 1 ) is to be placed, and a roller die guiding face ( 6 ) which is lower in level than an upper face of the blank ( 1 ) in the blank housing recess ( 5 ) is horizontally formed in an outer periphery of the blank housing recess ( 5 ). The slotting roller die ( 11 ) has a blade edge ( 12 ) on its outer periphery, and, while the slotting roller die is rotated in synchronization with the blank ( 1 ) about the roller axis which is inclined with respect to the rotation axis of the upper and lower rotary dies ( 4 ), the blade edge ( 12 ) is slid on the roller die guiding face ( 6 ) in an inward radial direction to be pressed against an outer peripheral portion ( 10 ) of the blank ( 1 ) which is protruded from the blank housing recess ( 5 ), whereby the outer peripheral portion ( 10 ) is slit into two parts in the thickness direction to form slotted parts ( 10   a,    10   b ).

This application is a 35 USC 371 of PCT/JP00/01447, filed Mar. 10, 2000.

TECHNICAL FIELD

The present invention relates to a slotting method in which, duringproduction of a metal sheet V-pulley, a metal sheet brake shoe, or thelike, an outer peripheral portion of a blank is split into two parts inthe thickness direction, a slotting device, and a method ofmanufacturing a metal sheet brake shoe by slotting.

BACKGROUND ART

As a slotting method in which, during production of a metal sheetV-pulley, an outer peripheral portion of a disk-like blank is split intotwo parts in the thickness direction, for example, a slotting method isdisclosed in Japanese Patent No. 2520095. In the slotting method, theouter peripheral portion of a disk-like metal blank is slit in thethickness direction into two parts by a slotting roller die. In theslotting roller die used in the method, an edge-like blade portion isprotruded in the circumferential direction in an axial center portion ofthe outer peripheral face. While pressing the edge-like blade portionagainst a center portion in the thickness direction of the outerperipheral face of the blank, the slotting roller die and the blank aresynchronously rotated, whereby the outer peripheral portion of the blankis slit into two parts in the thickness direction.

In the above-mentioned slotting method, the edge of the blade portion ofthe slotting roller die easily slips over the outer peripheral face ofthe blank in the thickness direction during an initial stage of theslotting process, and hence it is not easy to slot the outer peripheralface of the blank at an arbitrary position in the thickness direction.In the case where a thin blank is used, particularly, instability anddifficulty of centering and equal slitting in the process of slotting acenter portion in the thickness direction of the outer peripheral faceof the blank are conspicuous.

It is an object of the invention to provide a slotting method in whichslitting can be correctly easily performed at an arbitrary position inthe thickness direction of an outer peripheral face of a blank, aslotting device for the method, and a method of manufacturing a metalsheet brake shoe by slotting.

DISCLOSURE OF INVENTION

The slotting method of the invention is a slotting method in which adisk-like metal blank is clampingly held between upper and lower rotarydies, a slotting roller die is pressed against an outer peripheralportion of the blank, and the outer peripheral portion of the blank issplit into two parts in a thickness direction, wherein a blank housingrecess a depth of which is smaller than a thickness of the blank isformed in an upper face of the lower rotary die on which the blank is tobe placed, a roller die guiding face is formed horizontally andcontinuously with an outer periphery of an upper end of an outerperipheral wall of the blank housing recess to be lower in level than anupper face of the blank in the blank housing recess, the upper rotarydie is formed to have an outer diameter which is smaller than an outerdiameter of the lower rotary die, thereby allowing an upper face of theouter peripheral portion of the blank in the blank housing recess to beexposed, the slotting roller die has a blade edge on an outer peripheryof the die, and, while the slotting roller die is rotated insynchronization with the blank about a roller axis which is inclinedwith respect to a rotation axis of the upper and lower rotary dies, theblade edge is slid on the roller die guiding face in an inward radialdirection to be pressed against the outer peripheral portion of theblank which is protruded from the blank housing recess, whereby theouter peripheral portion is slit into two parts in the thicknessdirection.

According to this method, slotting can be surely performed at a position(slotting position) which is in the outer peripheral portion of theblank protruded from the blank housing recess of the lower rotary die,and which coincides with the level of the roller die guiding face,without causing a positional displacement by the blade edge of theslotting roller die which is slid along the roller die guiding face.When the outer peripheral portion of the blank is to be slit into twoparts of the same thickness in the thickness direction, for example, thecenter portion in the thickness direction of the outer peripheralportion of the blank can be therefore surely slotted simply by housingthe blank in the blank housing recess so that only a portion of a halfof the thickness of the blank is protruded. Namely, when the blank ishoused in the blank housing recess so that a desired slotting positionof the outer peripheral portion of the blank corresponds to the level ofthe roller die guiding face, slitting can be performed correctly andeasily at an arbitrary position in the thickness direction of the outerperipheral portion of the blank. Under a state where the whole of theblank including an outer peripheral portion is supported in the housingrecess of the lower rotary die, the outer peripheral portion of theblank can be slotted stably and surely. Therefore, the method is optimumfor slotting an outer peripheral portion of a blank of a reducedthickness.

In the slotting method of the other invention, after an outer peripheralportion of a blank which is protruded from a blank housing recess of alower rotary die is slotted into two parts in a thickness direction toform upper and lower slotted parts by a blade edge of a slotting rollerdie in the same manner as the above-mentioned slotting method, the blankis further clampingly held between second upper and lower rotary dies sothat the upper and lower slotted parts are outward protruded from outerperipheral faces of the upper and lower rotary dies, and an expandingblade portion of an expandingly forming roller die is pressed againstthe slotted parts, the expanding blade portion being formed on an outerperipheral face in a circumferential direction, to straight expand theslotted parts in upward and downward directions.

According to this method, it is possible to easily produce a slottedproduct of a shape having: a web which is configured by a part of theblank that is clamped between the second upper and lower rotary dies;and rims which are configured respectively by the slotted parts that areformed continuously with an outer peripheral portion of the web.

The slotting device of the other invention is a slotting devicecomprising: upper and lower rotary dies which clampingly hold adisk-like metal blank; and a slotting roller die which, while beingrotated in synchronization with the blank, presses a blade edge againstan outer peripheral portion of the blank to slit the outer peripheralportion into two parts in a thickness direction, wherein a blank housingrecess a depth of which is smaller than a thickness of the blank isformed in an upper face of the lower rotary die on which the blank is tobe placed, a roller die guiding face is formed horizontally andcontinuously with an outer periphery of an upper end of an outerperipheral wall of the blank housing recess to be lower in level than anupper face of the blank in the blank housing recess, the upper rotarydie is formed to have an outer diameter which is smaller than an outerdiameter of the lower rotary die, to allow an upper face of the outerperipheral portion of the blank in the blank housing recess to beexposed, the slotting roller die has a blade edge on an outer peripheryof the die, and, while the slotting roller die is rotated insynchronization with the blank about a roller axis which is inclinedwith respect to a rotation axis of the upper and lower rotary dies, theblade edge is slid on the roller die guiding face in an inward radialdirection to be pressed against the outer peripheral portion of theblank which is protruded from the blank housing recess.

As a result of the use of the device, when the blank is housed in theblank housing recess so that a desired slotting position of the outerperipheral portion of the blank corresponds to the level of the rollerdie guiding face, slitting can be performed correctly at an arbitraryposition in the thickness direction of the outer peripheral portion ofthe blank.

Furthermore, the method of manufacturing a metal sheet brake shoe of theother invention is a method of, by using a disk-like metal blank,manufacturing a metal sheet brake shoe having a shoe rim which has apartially arcuate shape, and a shoe rib which is protruded from an innerperiphery of the shoe rim, and includes: the slotting step of splittingan outer peripheral portion of the blank which is protruded from a blankhousing recess of a lower rotary die, by a blade edge of a slottingroller die into two parts in a thickness direction to form upper andlower slotted parts; an expandingly forming step in which the blank isclampingly held between second upper and lower rotary dies so that theupper and lower slotted parts are outward protruded from outerperipheral faces of the upper and lower rotary dies, and an expandingblade portion of an expandingly forming roller die is pressed againstthe slotted parts, the expanding blade portion being formed on an outerperipheral face in a circumferential direction, to straight expand theslotted parts in upward and downward directions, thereby shaping a webwhich is configured by a part of the blank clamped between the upper andlower rotary dies, and rims which are configured respectively by theslotted parts that annularly expand toward both sides in a thicknessdirection of an outer peripheral portion of the web; and a step ofcutting the web and the rims into a required shape, thereby forming abrake shoe having a shoe rim which has a partially arcuate shape, and ashoe rib which is protruded from an inner periphery of the shoe rim.

According to the method, a metal sheet brake shoe having a shoe rimwhich has a partially arcuate shape, and a shoe rib which is protrudedfrom an inner periphery of the shoe rim can be easily produced from adisk-like metal blank.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1A is a diagram illustrating a state before a slotting process of aslotting step in the slotting method.

FIG. 1B is a diagram illustrating the operation of the slotting step inthe slotting method.

FIG. 2A is a diagram illustrating a state before an expandingly formingprocess in an expandingly forming step in the slotting method.

FIG. 2B is a diagram illustrating the operation of the expandinglyforming step in the slotting method.

FIG. 3A is a diagram illustrating a state before a finishing process ina finishing step in the slotting method.

FIG. 3B is a diagram illustrating the operation of the finishing step inthe slotting method.

FIG. 4 is a section view showing main portions of another example of alower rotary die which is used in the slotting method.

FIG. 5 is a section view of a metal sheet poly-V pulley which isobtained from a slotted product.

FIG. 6 is a section view of a metal sheet back face pulley which isobtained from a slotted product.

FIG. 7 is a section view of a metal sheet brake shoe which is obtainedfrom a slotted product.

FIG. 8 is a front view illustrating a cutting step in steps ofmanufacturing the metal sheet brake shoe shown in FIG. 7.

FIG. 9 is a section view showing another example of a slotted product.

BEST MODE FOR CARRYING OUT THE INVENTION

In the slotting method of the invention, first, a metal blank 1 such asa steel plate which is formed into a disk-like shape by a press formingas shown in FIG. 1A is used in a slotting step. A center hole 2 isformed in the blank 1. The blank 1 is clampingly held between a firstupper rotary die 3 and a lower rotary die 4. A blank housing recess 5for housing the blank 1 is annularly formed in the upper face of thelower rotary die 4 on which the blank 1 is to be placed. A roller dieguiding face 6 is formed horizontally and continuously with the outerperiphery of the upper end of an outer peripheral wall 5 a of the blankhousing recess 5.

An annular boss 7 onto which the center hole 2 of the blank 1 is to befitted is formed in the inner periphery side of the blank housing recess4 so that the center of the boss coincides with the rotation axis of theupper and lower rotary dies 3, 4, and the upper face 7 a of the boss 7is flush with the upper face 1 a of the blank 1 in the blank housingrecess 5. A protrusion 9 which is protruded from the center of the lowerface of the lower rotary die 2 is to be concentrically fitted into acenter recess 8 surrounded by the annular boss 7.

The outer diameter of the upper rotary die 3 is smaller than that of thelower rotary 4 so that an outer peripheral portion 10 of the blank 1 inthe blank housing recess 5 is exposed in a range which is outer than theouter peripheral face 3 a of the upper rotary die 3 in the extentcorresponding to a slotting depth of a predetermined degree.

The depth of the blank housing recess 5 is smaller than the thickness ofthe blank 1 so that, when the blank 1 is housed, the upper face 1 a ofthe blank 1 is upward protruded from the roller die guiding face 6. Aposition of the outer peripheral portion 10 of the blank 1 in the blankhousing recess 5 which coincides with the level of the roller dieguiding face 6 serves as a slotting position. In specific relationshipsbetween the thickness of the blank 1 and the depth of the blank housingrecess 5, when slotting is to be performed on a center portion in thethickness direction of the outer peripheral portion 10 of the blank 1,for example, the blank 1 is therefore housed in the blank housing recess5 so that only a portion of a half of the total thickness is upwardprotruded from the roller die guiding face 6. In the case where theouter peripheral portion 10 of the blank 1 is to be slotted at athickness ratio of 1:2 with respect to the thickness direction, theblank 1 is housed in the blank housing recess 5 so that a portion of athickness which is ⅓ or ⅔ of the total thickness is upward protrudedfrom the roller die guiding face 6. Namely, slotting can be performed atan arbitrary position in the thickness direction of the outer peripheralportion 10 of the blank 1 by changing the degree of protrusion of theblank 1 from the blank housing recess 5.

In the slotting step, a slotting roller die 11 is prepared. The slottingroller die 11 has a blade edge 12 of a substantially V-like sectionshape, in the outer periphery. The blade edge 12 is placed on one sideof the upper and lower rotary dies 3, 4 so as to be radially slid to bemovable advanceably and retractably on the roller die guiding face 5 ofthe lower rotary die 4. In this case, the slotting roller die 11 isplaced so that the roller axis O₂ is inclined with respect to therotation axis O₁ of the upper and lower rotary dies 3, 4, therebyallowing the outer peripheral portion 10 of the blank 1 to be easilyslotted by the blade edge 12. A clearance angle α (for example, about5°) is formed in order to prevent the back 12 a of the blade edge 12from colliding against the roller die guiding face 6 to seize up. Inorder to prevent from the blade edge 12 from seizing, a lubricant ofhigh abrasion resistance may be applied to the roller die guiding face6. The face 12 b of the blade edge 12 is formed as a concave surface.

In the slotting process, while the slotting roller die 11 and the blank1 are synchronously rotated, the slotting roller die 11 is moved toapproach the outer peripheral portion 10 of the blank 1 as indicated bythe arrow a in FIG. 1A to slide the blade edge 12 on the roller dieguiding face 6 in an inward radial direction, whereby the blade edge 12is pressed against the outer peripheral portion 10 of the blank 1 whichis protruded from the blank housing recess 5 in the outside of the upperrotary die 3, to split the outer peripheral portion 10 into two parts inthe thickness direction. An upper slotted part 10 a which is scooped bythe face 12 b of the blade edge 12 on one side with sliding thereon israised so as to be separated from a lower slotted part 10 b which is inthe blank housing recess 5 on the other side. FIG. 1B shows the slottedstate. In this case, slotting can be performed at an arbitrary positionin the thickness direction of the outer peripheral portion 10 of theblank 1 by changing the degree of protrusion of the blank 1 from theblank housing recess 5.

As the formation of the two or upper and lower slotted parts 10 a, 10 bfrom the outer peripheral portion 10 of the blank 1 as a result ofpressing of the slotting roller die 11 is further advanced, a phenomenonthat the material of the blank 1 is pulled and moved in the outerperipheral direction occurs. This causes the center hole 2 of the blank1 to be easily deformed in a direction along which the diameter of thehole is increased. In order to prevent the deformation from occurring,preferably, the blank 1 is housed in the blank housing recess 5 in sucha manner that at least a lower edge portion 100 a of the outermostperipheral face 100 of the outer peripheral portion 10 of the blankabuts against the outer peripheral wall 5 a of the blank housing recess5 as shown in FIG. 1A, whereby the above-mentioned material movingphenomenon of the blank 1 is blocked. The outer peripheral wall 5 a ofthe blank housing recess 5 may be formed as a straight wall which isperpendicular to an inner bottom face 5 b of the recess. In order toenable the blank 1 to be easily fitted into the housing recess 5,alternatively, it is preferable to, as shown in FIG. 1A, form a taperedportion 13 over the whole length in the height direction of the outerperipheral wall 5 a, or to, as shown in FIG. 4, form a tapered portion13 in only the edge where the upper end of the outer peripheral wall 5 aintersects with the roller die guiding face 6.

The blank 1 which has undergone the slotting process as described aboveis transferred to the next expandingly forming step. In the expandinglyforming step, as shown in FIG. 2A, second upper and lower rotary dies14, 15 having the same outer diameter, and an expandingly forming rollerdie 16 are used. The expandingly forming roller die 16 is formed so thatan expanding blade portion 17 having a mountain-like section shape isprotruded in the circumferential direction in an axial center portion ofthe outer peripheral face of the die, and grooves 18 a , 18 b having anarcuate section shape are formed respectively in upper and lower side inthe axial direction of the expanding blade portion 17. The blank 1 isclampingly held between the second upper and lower rotary dies 14, 15 sothat the upper and lower slotted parts 10 a , 10 b are outward protrudedfrom outer peripheral faces 14 a , 15 a of the upper and lower rotarydies 14, 15. The expandingly forming roller die 16 is moved to approachthe blank 1 as indicated by the arrow b in FIG. 2A, whereby, as shown inFIG. 2B, while the slotted parts 10 a , 10 b are slid in the grooves 18a , 18 b , the slotted parts 10 a , 10 b are respectively pressedagainst the outer peripheral faces 14 a , 15 a of the upper and lowerrotary dies 14, 15, to be straight expanded in upward and downwarddirections. As a result, a slotted product having a shape in which a web19 configured by a part of the blank 1 that is clamped between the upperand lower rotary dies 14, 15, and rims 20 a, 20 b respectivelyconfigured by the slotted parts 10 a , 10 b that annularly expand towardboth sides in the thickness direction of an outer peripheral portion ofthe web 19 is obtained.

In the finishing step, as shown in FIG. 3A, a finishing roller die 21 isused in which a width rectifying groove 22 is formed in an outerperipheral face 21 a in the circumferential direction. The finishingroller die 21 is moved to approach the rims 20 a , 20 b as indicated bythe arrow c in FIG. 3A, and the rims 20 a , 20 b are pressed furtherstrongly by the width rectifying groove 22 against the outer peripheralfaces 14 a , 15 a of the upper and lower rotary dies 14, 15, whereby therims 20 a , 20 b can be finished so as to be straight and have apredetermined width dimension as shown in FIG. 3B. In the case where arecess 20 c remains in the center of the rims 20 a , 20 b as shown inFIG. 3A even after the previous step, also a process of eliminating therecess 20 c is performed. Preferably, the inner bottom face 22 a of thewidth rectifying groove 22 is rounded to a radius of about 200 R (seethe broken line P in FIG. 3A) rather than that the inner bottom face isformed as a perpendicular face parallel to the axis, because the rims 20a , 20 b can be prevented from being warped by residual stress asindicated by the phantom line G (see FIG. 3B), so as to be finishedstraight in the width direction.

The slotted product in which the rims 20 a , 20 b are formed on theouter periphery of the web 19 in this way can be further processed inthe next step in the following manner.

For example, a single V-groove may be formed in the outer periphery ofthe rims 20 a , 20 b to produce a metal sheet V-pulley (not shown), orpoly-V grooves 23 a may be formed in one of or both of the rims 20 a ,20 b as shown in FIG. 5 to produce a metal sheet poly-V-pulley 23. As aslotted product which is used for producing the metal sheetpoly-V-pulley 23 shown in FIG. 5, a product in which a boss 19 asurrounding the center hole 2 is formed in the center of the web 19 isused. Alternatively, in the above-mentioned slotted product, the outerperipheral faces of the rims 20 a , 20 b may be finished into a convexarcuate shape as shown in FIG. 6 so as to produce a metal sheet backface pulley 24. As shown in FIG. 7, furthermore, a metal sheet brakeshoe 25 may be produced.

The case where the metal sheet brake shoe 25 which is shown in FIG. 7,and which is to be used in a drum brake is produced by using theabove-mentioned slotted product will be described.

As shown in FIG. 8, the above-mentioned slotted product in which therims 20 a , 20 b are formed on the outer periphery of the web 19 is cutinto a desired shape along the cutting plane line C by laser or plasmafusing. As a result, it is possible to easily obtain the metal sheetbrake shoe 25 having a shoe rim 25 a which has a partially arcuate shapeconfigured by parts of the rims 20 a , 20 b as shown in FIG. 7, and ashoe rib 25 b which is protruded from the inner periphery of the shoerim 25 a , and which is configured by a part of the web 19. As shown inFIG. 7, thereafter, a friction lining 26 is bonded to the outer face ofthe shoe rim 25 a of the brake shoe 25. In order to enhance the bondingstrength of the friction lining 26, a knurling process is preferablyapplied to the outer face of the shoe rim 25 a before the process ofbonding the friction lining 26.

The blank 1 which has been slotted as shown in FIG. 1B may be shaped sothat, as shown FIG. 9, the upper slotted part 10 a is perpendicular tothe lower slotted part 10 b , so as to be formed into a slotted producthaving a shape in which a boss 27 configured by the slotted part 10 a ison one face of the web 19 having the center hole 2.

Industrial Applicability

According to the invention, during production of a metal sheet productsuch as a metal sheet v-pulley or a metal sheet brake shoe, slotting canbe correctly easily performed at an arbitrary position in the thicknessdirection of an outer peripheral portion of a blank, so that theaccuracy and quality of a metal sheet product can be improved.

What is claimed is:
 1. A slotting method in which a disk-like metalblank is clampingly held between upper and lower rotary dies, a slottingroller die is pressed against an outer peripheral portion of said blank,and said outer peripheral portion of said blank is split into two partsin a thickness direction, wherein a blank housing recess a depth ofwhich is smaller than a thickness of said blank is formed in an upperface of said lower rotary die on which said blank is to be placed, aroller die guiding face is formed horizontally and continuously with anouter periphery of an upper end of an outer peripheral wall of saidblank housing recess to be lower in level than an upper face of saidblank in the said blank housing recess, said upper rotary die is formedto have an outer diameter which is smaller than an outer diameter ofsaid lower rotary die, thereby allowing an upper face of said outerperipheral portion of said blank in said blank housing recess to beexposed, said slotting roller die has a blade edge on an outer peripheryof said die, and, while said slotting roller die is rotated insynchronization with said blank about a roller axis which is inclinedwith respect to a rotation axis of said upper and lower rotary dies,said blade edge is slid on said roller die guiding face in an inwardradial direction to be pressed against said outer peripheral portion ofsaid blank which is protruded from said blank housing recess, wherebysaid outer peripheral portion is slit into two parts in the thicknessdirection.
 2. A slotting method according to claim 1, wherein said blankis housed in said blank housing recess in such a manner that at least alower edge portion of an outermost peripheral face of said outerperipheral portion of said blank abuts against said outer peripheralwall of said blank housing recess.
 3. A slotting method in which adisk-like metal blank is clampingly held between upper and lower rotarydies, a slotting roller die is pressed against an outer peripheralportion of said blank, and said outer peripheral portion of said blankis split into two parts in a thickness direction, wherein a blankhousing recess a depth of which is smaller than a thickness of saidblank is formed in an upper face of said lower rotary die on which saidblank is to be placed, a roller die guiding face is formed horizontallyand continuously with an outer periphery of an upper end of an outerperipheral wall of said blank housing recess to be lower in level thanan upper face of said blank in the said blank housing recess, said upperrotary die is formed to have an outer diameter which is smaller than anouter diameter of said lower rotary die, thereby allowing an upper faceof said outer peripheral portion of said blank in said blank housingrecess to be exposed, said slotting roller die has a blade edge on anouter periphery of said die, and, while said slotting roller die isrotated in synchronization with said blank about a roller axis which isinclined with respect to a rotation axis of said upper and lower rotarydies, said blade edge is slid on said roller die guiding face in aninward radial direction to be pressed against said outer peripheralportion of said blank which is protruded from said blank housing recess,whereby said outer peripheral portion is slit into two parts in thethickness direction to form upper and lower slotted parts, said blank isthen clampingly held between second upper and lower rotary dies so thatsaid upper and lower slotted parts are outward protruded from outerperipheral faces of said upper and lower rotary dies, and an expandingblade portion of an expandingly forming roller die is pressed againstsaid slotted parts, said expanding blade portion being formed on anouter peripheral face in a circumferential direction, to straight expandsaid slotted parts in upward and downward directions.
 4. A slottingdevice comprising: upper and lower rotary dies which clampingly hold adisk-like metal blank; and a slotting roller die which, while beingrotated in synchronization with said blank, presses a blade edge againstan outer peripheral portion of said blank to slit said outer peripheralportion into two parts in a thickness direction, wherein a blank housingrecess a depth of which is smaller than a thickness of said blank isformed in an upper face of said lower rotary die on which said blank isto be placed, a roller die guiding face is formed horizontally andcontinuously with an outer periphery of an upper end of an outerperipheral wall of said blank housing recess to be lower in level thanan upper face of said blank in said blank housing recess, said upperrotary die is formed to have an outer diameter which is smaller than anouter diameter of said lower rotary die, to allow an upper face of saidouter peripheral portion of said blank in said blank housing recess tobe exposed, said slotting roller die has a blade edge on an outerperiphery of said die, and, while said slotting roller die is rotated insynchronization with said blank about a roller axis which is inclinedwith respect to a rotation axis of said upper and lower rotary dies,said blade edge is slid on said roller die guiding face in an inwardradial direction to be pressed against said outer peripheral portion ofsaid blank which is protruded from said blank housing recess.
 5. Amethod of, by using a disk-like metal blank, manufacturing a metal sheetbrake shoe having a shoe rim which has a partially arcuate shape, and ashoe rib which is protruded from an inner periphery of said shoe rim,wherein said method includes: a slotting step of clampingly holding adisk-like metal blank between upper and lower rotary dies, and pressinga slotting roller die against an outer peripheral portion of said blank,thereby splitting said outer peripheral portion of said blank into twoparts in a thickness direction, and, in this step, a blank housingrecess a depth of which is smaller than a thickness of said blank isformed in an upper face of said lower rotary die on which said blank isto be placed, a roller die guiding face is formed horizontally andcontinuously with an outer periphery of an upper end of an outerperipheral wall of said blank housing recess to be lower in level thanan upper face of said blank in said blank housing recess, said upperrotary die is formed to have an outer diameter which is smaller than anouter diameter of said lower rotary die, to allow an upper face of saidouter peripheral portion of said blank in said blank housing recess tobe exposed, said slotting roller die has a blade edge on an outerperiphery of said die, and, while said slotting roller die is rotated insynchronization with said blank about a roller axis which is inclinedwith respect to a rotation axis of said upper and lower rotary dies,said blade edge is slid on said roller die guiding face in an inwardradial direction to be pressed against said outer peripheral portion ofsaid blank which is protruded from said blank housing recess, wherebysaid outer peripheral portion is slit into two parts in the thicknessdirection to form upper and lower slotted parts; an expandingly formingstep in which said blank is clampingly held between second upper andlower rotary dies so that said upper and lower slotted parts are outwardprotruded from outer peripheral faces of said upper and lower rotarydies, and an expanding blade portion of an expandingly forming rollerdie is pressed against a portion between said slotted parts, saidexpanding blade portion being formed on an outer peripheral face in acircumferential direction, to straight expand said slotted parts inupward and downward directions, thereby shaping a web which isconfigured by a part of said blank clamped between said upper and lowerrotary dies, and rims which are configured respectively by said slottedparts that expand toward both sides in a thickness direction of an outerperipheral portion of said web; and a step of cutting said web and saidrims into a required shape, thereby forming a brake shoe having a shoerim which has a partially arcuate shape, and a shoe rib which isprotruded from an inner periphery of said shoe rim.